202211201858
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Tags: HPA axis Glucocorticoids

Cortisol is a glucocorticoid hormone released by the Adrenal Cortex due to HPA axis activity.

Effects

Acute

• Control of stress responsiveness
  • MR: control sensitivity of stress response system (set threshold)
  • GR: restrain stress-induced responses (negative feedback)
• Mobilization of energy (GR)
• Suppression of immunity (anti-inflammatory, GR)
• Behavioral inhibition/attention (mPFC, GR)
• Motivation (OFC, NAc, GR)
• Information processing (hippocampus)

Dexamethasone Suppression Test

Dexamethasone is a specific GR agonist (not MR) which can be used to test reactive cortisol. In patients with MDD, increased CORT levels (“increased non-suppression”) in response to DEX (or CRH!)

The DST measures response of adrenal glands to ACTH. DEX should decrease ACTH in healthy individuals, which should reduce cortisol levels through the inhibitory feedback loop. DEX acts on the Pituitary Gland to reduce secretion of ACTH and reduce secretion of hormones from adrenal cortex.

DEX is administered and levels of cortisol are measured. The cortisol levels should decrease in response to the administration of DEX. This can be done with a low-dose (1mg at 11 p.m., blood drawn at 8 a.m. for cortisol measurement, or 3-day urine collection), or high-dose (baseline cortisol is measured, then 8mg DEX at 11 p.m., blood measurement at 8 a.m., or 3–day urine collection).

Drugs that act on it

You don’t want to mess with your natural cortisol cycles.

Reduce

• tongkat ali
• ashwagandha
• Phosphatidylserine
• Rhodiola rosea
• Schisandra
• Holy basil
• Apigenin
• Panax ginseng
• Licorice root

Mimic

• Panax ginseng